1. Field of the Invention
This invention relates to an electronic still camera, and more particularly to an optical system suitable for TTL direct dimming in an auto-strobe device of an electronic still camera.
2. Description of the Related Art
The auto-strobe device has such an arrangement that a stroboscope is actually caused to luminesce during stroboscopic photographing, a light reflected by a subject is measured to control the exposure by real time, namely, the light reflected by the subject is photo-electrically transduced by a dimming sensor, electric signals thus photo-electrically transduced are integrated by an integrating circuit, and, when the electric signals thus integrated reach a value corresponding to proper exposure, the luminescence of the stroboscope is stopped.
Heretofore, in the auto-strobe device of a camera using a silver salt film, there has been used one in which a dimming sensor for measuring a light reflected by a film surface such as SPD is provided in a main body of the camera for conducing TTL dimming.
Now, in the electronic still camera, a solid state image sensing device is provided in place of the silver salt film, and further, an optical low-pass filter and the like are provided in front of the solid state image sensing device, for thus presenting such a problem that it is difficult to provide the dimming sensor for TTL direct dimming in the vicinity of a taking shutter.